Process of manufacturing a laminated product

ABSTRACT

A process of manufacturing a laminated product, comprises the steps of: providing a carrier film; coating the film with a lacquer; applying a metal layer to the lacquer on the carrier film; applying a protective coating material to the metal layer; curing the protective coating material using UV-light (or EB radiation); applying a water based adhesive to the protective coating layer; applying a water permeable substrate to the adhesive layer; and removing the carrier film.

FIELD OF THE INVENTION

The invention relates to the field of manufacturing laminated products,in particular high gloss sheets having particular barrier properties.Such sheet products are used for instance as labels, wrappings etc.

BACKGROUND OF THE INVENTION

Widely used manufacturing process is transfer metallizing. This processemploys the stages of coating a carrier film, metallizing the coating,laminating the coated, metallized carrier film to a substrate, andfinally removing the carrier film from the substrate. Such a transfermetallizing process is described in U.S. Pat. No. 4,344,998. Thesubstrate is adhered to the coated, metallized carrier film by means ofa so-called dry adhesive, that is an adhesive which had been dissolvedin an organic solvent.

After application of this adhesive, the solvent has to be evaporated bymeans of drying ovens. Subsequently, the dried adhesive is brought intocontact with the substrate, is then allowed to cure in such a way thatfinally, after the adhesive is hard enough, the carrier film can beremoved.

This known process has several disadvantages. First of all, the driedadhesive is not very mobile. This means that it cannot provide goodpenetration and thereby adherence to a rough surface, such as uncoatedpaper or board, because it is difficult to penetrate such irregularlyshaped surface due to its very high viscosity after evaporation of thesolvent.

Moreover the adhesive takes time to harden before the carrier film canbe separated from the product. Only after such time has elapsed, is itpossible to check whether the bond between substrate and metal layer isstrong enough. This of course represents an economic disadvantage.

It is also known to use a so-called wet adhesive, that is a water basedadhesive. Such a process is described in GB-A-2006109. The water basedadhesive is applied to the coated, metallized carrier film andsubsequently the substrate is laminated without drying the adhesive. Thesubstrate must have an absorbent character, such as board or paper,which absorbs the water from the adhesive.

This process has the advantage that the adhesive is hard as soon as thewater is absorbed by the substrate. Thereby, the carrier film can beremoved even in-line, directly after laminating the substrate. Moreover,relatively cheap uncoated and/or recycled papers and boards can be usedin this process, thus giving high quality products with high internalstrength at high production speeds, and at low cost.

The disadvantage of this process however is that it cannot provide verygood barrier properties, in particular with respect to gasses. First ofall, the rough, uncoated surface of the papers and boards used causesthe metal layer to become distorted and broken up. Moreover, the papersand boards, due to the composition of cellulose fibers, are greatlyaffected by changes in humidity. As the humidity increases, the paper orboard expands; as the humidity decreases, they contract. As a result,the metal layer is caused to break leading to a loss of barrierproperties.

SUMMARY OF THE INVENTION

The object of the invention is to provide a process for manufacturingsuch paper or board based product which still have the desired barrierproperties, while maintaining the high gloss appearance thereof.According to the invention, a process of manufacturing a laminatedproduct is provided, comprising the steps of:

providing a carrier film,

coating the film with a lacquer,

applying a metal layer to the lacquer on the carrier film,

applying a protective coating material to the metal layer,

curing the protective coating material,

applying a water based adhesive to the protective coating layer,

applying a water permeable substrate to the adhesive layer, and

removing the carrier film.

The protecting coating layer protects the metal layer from thedimensional changes which occur in the substrate as a result of thevarying humidity thereof. Thus, the barrier function of the metal layercan be maintained; moreover, the protective coating itself providesadditional barrier properties.

Preferably, the coating material is cured by means of UV-light or EBradiation.

Curing the protecting coating layer by means of UV-light (or EBradiation) ensures a rapid process step. This is enhanced by the factthat only a small amount of coating has to be applied on the very smoothmetal layer.

As soon as the substrate is applied to the carrier film, the waterpenetrates into the surface thereof. As a result, the adherence of thesubstrate takes place in a very rapid manner, and directly thereafterthe carrier film can be removed.

The release agent can be a lacquer with a zero contact angle.

In order to obtain even better barrier properties, preferably thecarrier film consists of polyester. The surface smoothness of thepolyester film is copied onto the metal layer, resulting in excellentbarrier properties of the latter.

BRIEF DESCRIPTION OF THE DRAWINGS

The process according to the invention will be explained further withreference to the drawing.

The FIGURE depicts a laminated product according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the drawing, a carrier film 1 is shown, which in a first process stepis provided with a release layer 2. Onto this release layer 2, metallayer 3 has been applied by means of a vacuum depositing process.

Subsequently, a protecting coating 4 is coated and cured onto the metallayer 3, whereafter wet adhesive 5 is applied onto the protectingcoating. A suitable amount of adhesive is 4-6 grams per square meter.

Thereafter, a paper or board sheet 6 is laminated onto the adhesive. Thewet adhesive easily penetrates into the rough surface 7 of the paper orboard substrate 6. Immediately the liquid such as water migrates intothe paper or board material, leaving a dry adhesive 8 which provides therequired bonding strength.

As a result, directly after applying the substrate 6, the carrier filmmay be removed as indicated at 9. Thus, it is possible to remove thecarrier film in line, resulting in an efficient and quick manufacturingprocedure.

I claim:
 1. Process of manufacturing a laminated product, comprising thesteps of:providing a carrier film, coating the film with a lacquer,applying a metal layer to the lacquer on the carrier film, applying aprotective coating material to the metal layer, curing the protectivecoating material, applying a water based adhesive to the protectivecoating layer, applying a water permeable substrate to the adhesivelayer, and removing the carrier film.
 2. Process according to claim 1,whereby the protective coating is cured by means of UV-light or electronbeam (EB) radiation.
 3. Process according to claim 1, wherein thesubstrate is a paper or board.
 4. Process according to claim 1, whereinthe lacquer has a zero contact angle.
 5. Process according to claim 1,wherein the carrier film consists of polyester.
 6. Process according toclaim 2, wherein the substrate is a paper or board.
 7. Process accordingto claim 2, wherein the lacquer has a zero contact angle.
 8. Processaccording to claim 3, wherein the lacquer has a zero contact angle. 9.Process according to claim 2, wherein the carrier film consists ofpolyester.
 10. Process according to claim 3, wherein the carrier filmconsists of polyester.
 11. Process according to claim 4, wherein thecarrier film consists of polyester.